References for IDS inclusion:                Re. 34,976 (cell phone digital recorder/live conversations)        U.S. Pat. No. 6,064,792 (Fox) deferred recording.        U.S. Pat. No. 4,495,647 (Burke) Digital voice storage mobile.        U.S. Pat. No. 5,519,684 (Iizuka) Digital recorder, multiple tracks.        U.S. Pat. No. 5,995,824 (Whitfield) cell phone vox.        U.S. Pat. No. 5,867,793 (Davis) cell phone vox.        U.S. Pat. No. 3,936,610 (Schiffman) switching controller—output.        
Mobile phones (Cellular Phones) have become a standard form of communication in industrialized countries. Communications with people in local and wide area cell networks is common place. An artifact of this form of modem communications is many times it is difficult to hear the voice of a person over a mobile phone. This difficulty stems from both technological and environmental short comings inherent in the communication type.
A mobile phone network is an intricate and complex array of devices. For easy reference this disclosure describes a GSM (Global System for Mobile Communication) style digital mobile phone system. However the invention herein is not limited particularly to this type of system. Generally a GSM is composed of a number of Mobile Service Centers (MSC) and an integrated Visitor Location Register (VLR) therein. The MSC/VLR areas include a number of Location Areas (LA) which are defined as part of a given MSC/VLR area. Mobile sets (MS), or mobile phone subscribers, may freely roam within the coverage area without having to send update location information to the MSC/VLR area that controls the LA. The cellular network is composed of all these elements and a multitude of subscribers, each having a mobile set (MS).
The wide spread use of mobile phones has produced a variety of different cellular networks. Cellular networks within the same region may operate on a different technology base. Some networks experience technical difficulties in the transmission and reception of signal from the MS to the Base Station (BS), the cellular networks reception area for receiving and transmitting information to each MS. These technical difficulties include interference from any number of signal producing sources (including other subscribers), geographical interference, structural interference and the like. The various source can individually or in combination contribute to poor reception of signal from the BS to MS, or for some error in signal from one station to the receiving station (MS/BS) causing the transmission to be garbled or difficult to interpret.
Additionally, the environment where mobile sets are often used in include places where a subscriber may not be able to dedicate their full attention to the conversation on a cell phone (e.g. when driving an automobile) or when the local area the subscriber is in makes hearing difficult (as in an areas having a lot of background noise). To assist in this problem there have been numerous recent developments to allow a subscriber to record information either during or after a conversation, using their MS as either a note pad, dictation device, or recorder for conversations. In all cases the use of the cellular phone as a data storage device produces undesired drawbacks and stretches the limitations of existing cellular phone technology. Some cell phones do offer a voice recording feature, either for live conversation or as a dictation machine. These recorders use existing technology and essentially combine two devices into one casing, instead of integrating a data recording system into the mobile set so that the available real estate and power of a mobile set are optimized.
The signal processing and data handling of a GSM phone utilizes technology which can be adapted for use with the present invention. Conventional GSM mobile phones possess an analog to digital signal converter (ADC) audio filter that converts analog microphone signal to digital speech samples at a sample rate of 8 KHz with 13 bits per sample. Voice encoders may process speech samples in 20 millisecond segments, where each segment is compressed into a speech frame of N bits. The actual number of bits per speech frame depends on the particular speech encoder used. The speech encoder may provide for half rate speech, fill rate, enhanced rate or variable rates for adaptive multi-rate speech. The encoder compresses speech so that the number of bits per second is minimized while still giving good quality speech. Voice encoder frames are interleaved and coded for error correction and detection and then transmitted to the base station.
Downlink voice operations, received through the base station, go through the inverse process of the voice encoder. A digital to analog (DAC) audio filter performs inverse operations of the ADC/audio filter in processing downlink speech frames. A voice activity detector (VAD) generates a binary flag (value 0 or 1) indicating whether the subscriber is speaking (value 0) or not (value 1). The VAD used in the GSM standard suppresses transmission during uplink, producing speech silence intervals to conserve the battery charge. It is possible to utilize much of the existing signal processing of a GSM compatible phone to enhance the data storage capacity of a mobile set, and record conversations.
It is an object of the present invention to provide a mobile set having sufficient memory capacity to store voice conversations.
Another objective of the present invention is to provide a means for allowing a subscriber to record a voice conversation in real time for later retrieval.
Another objective of the present invention is to provide a subscriber with the ability to record a conversation and recall the information somewhat contemporaneously in the same phone conversation.
Another object of the present invention is to provide a means to streamline the manner in which voice information is recorded, making greater effective use of the memory element within a subscriber's mobile set.
It is still a further objective of the present invention to allow subscribers to record both voice and data information into a mobile set memory element, and to provide accurate time indexing so the messages can be reproduced in the same form that they were transmitted in.
It is still a further objective of the present invention to provide a data file management system of data stored on the memory element for easy retrieval and sorting, either through the use of the MS or another device such as a desktop computer.
At least one of the present objectives is addressed in the following disclosure.